The present invention generally relates to a sample injector valve capable of introducing multiple samples of material into multiple liquid or gas streams. Such a valve is particularly useful for injecting multiple samples under pressure into a combinatorial chemistry system with moving streams of fluid, such as a parallel pressure reactor or a rapid flow analysis system using multi-channel or parallel chromatography and related techniques.
In combinatorial chemistry, a large number of candidate materials are created from a relatively small set of precursors and subsequently evaluated for suitability for a particular application. As currently practiced, combinatorial chemistry permits scientists to systematically explore the influence of structural variations in candidates by dramatically accelerating the rates at which they are created and evaluated. Compared to traditional discovery methods, combinatorial methods sharply reduce the costs associated with preparing and screening each candidate.
Combinatorial chemistry systems generally include apparatus for high throughput material synthesis as well as material evaluation. For example, WO 00/09255, incorporated herein by reference, discloses a parallel pressure reactor with methods and apparatus for synthesizing, screening and characterizing combinatorial libraries. Further, combinatorial systems may include flow characterization methods such as liquid chromatography or flow-injection analysis for the evaluation of a combinatorial library. Liquid chromatography and flow-injection analysis comprise methods of injecting a sample into a mobile phase of fluid to detect specific properties of the sample. For example, in liquid chromatography, a sample is injected into a mobile phase and passed through a chromatographic column. The chromatographic column then acts to separate one or more components of the sample by elution and the separated components are analyzed with a flow-through detector.
Traditional flow characterization systems have been designed primarily with respect to sample type and quality of information. However, in applying a traditional flow analysis apparatus in a combinatorial chemistry system, overall sample throughput is of a concern. Recent work directed at improving the efficiency of characterization and analysis for traditional flow analysis systems has focused on the total amount of analysis time required from sample preparation through detection. For example, Yoshida et al., U.S. Pat. No. 5,783,450 discloses a liquid chromatography system wherein parallel sample preparation reduces overall analysis time. WO 99/51980, incorporated herein by reference, discloses a method and system to increase sample throughput for the rapid characterization of polymers using a high pressure liquid chromatography apparatus.
However, the decrease in analysis time has not heretofore included an increase in the rate of delivery of samples for analysis. Even the aforementioned, improved flow analysis systems use conventional rotary sample injector valves wherein samples are loaded into sample loops for series injection into a mobile phase. Thus, the size of these conventional rotary valves limits the scale and number of channels that can be filled with samples. Such rotary injector valves can only inject one sample at a time into the mobile phase, placing further constraints on sample throughput. For example, WO 99/51980 discloses using different combinations of analysis steps both in series and in parallel to decrease the overall time spent on a sample but the systems disclosed use only a single rotary sample injector valve that can accommodate only one mobile phase. Thus, there is presently a need for a sample injector valve that can simultaneously inject multiple samples into multiple streams of fluid to further increase sample throughput in a combinatorial chemistry system.
Among the several objects and features of the present invention may be noted the provision of a sample injector valve for use in the rapid parallel injection of samples of material into a combinatorial chemistry system; the provision of such a valve which is of unitary, compact construction; the provision of such a valve which injects multiple samples with a single actuation; the provision of such a valve which cooperates with conventional automated injection apparatus and the provision of such a valve which augments combinatorial chemistry equipment.
Briefly, apparatus of this invention is a sample injector valve comprising a block and a shuttle for use in injecting samples into a combinatorial chemistry system. The block includes carrier fluid entry passages and carrier fluid exit passages. The carrier fluid entry passages are adapted for connection to a source of pressurized carrier fluid for urging carrier fluid to flow through the valve. The block further includes sample entry passages and sample vent passages. The shuttle is slidingly received in substantially sealing relationship to the block. The shuttle has transfer passages therein having sample collection volumes. An actuator is operatively connected to the shuttle for moving the shuttle in the valve between a first position in which samples of material to be analyzed can be collected in the shuttle and a second position in which collected samples can be fed into said carrier fluid exit passages for delivery to a combinatorial chemistry system. In the first position, at least some of the transfer passages of the shuttle are substantially in registration with respective ones of the sample entry passages and sample vent passages of the block for receiving a volume of sample material substantially equal to the sample collection volume of the transfer passage. In the second position, at least some of the transfer passages of the shuttle are substantially in registration with respective ones of said carrier fluid entry and exit passages for substantially simultaneous delivery of the multiple collected sample in the transfer passage into said carrier fluid exit passage under pressure of the carrier fluid.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.